since this is her THIRD rehab, she has by now been told/instructed about the tools to use for a successful recovery. continually sticking her back in rehab is not going to CURE her or as you say have this END. right now you are still paying her way while she gets to be "stubborn" and "slow to get with the program" - sounds like she's just riding the gravy train.....
i'm sorry, my snarky side is in rare form today.